QHeat licensed its patented geothermal well technology for a pilot project exploring the potential of deep geothermal energy in Estonia. Conducted in partnership with drilling, engineering, and consultation services provider Engineering Bureau Steiger and the Geological Survey of Estonia, the project represents a major milestone in QHeat’s international expansion.
For its first international licensing project, QHeat partnered with Engineering Bureau Steiger to deliver its patented coaxial heat well for the Geological Survey of Estonia. Steiger drilled a 712-meter deep heat well was drilled at the Arbavere research center in Estonia, to test low-temperature district heating and cooling.
To us, QHeat is the go-to partner in terms of geothermal energy.”
- Hardi Aosaar, Development Manager, Steiger
Additionally, QHeat provided consultation services for two other pilot projects in Estonia: a 500-meter deep well in Tallinn and five 500-meter deep wells near Roosna-Alliku. The projects began at the end of 2023 and reached its finish line in the beginning of 2025.
“We are working towards the decarbonization of heating. To us, QHeat is the go-to partner in terms of geothermal energy,” says Hardi Aosaar, Steiger’s Development Manager. Founded in Estonia, Steiger is a drilling, engineering, and consultation services provider with global operations.
According to Aosaar, deeper geothermal systems could play a crucial role in densely populated areas. This is where QHeat’s expertise comes into play.
QHeat’s geothermal wells reach depths of up to 2000 meters, which is much deeper than traditional geothermal heating solutions. QHeat’s technology is based on an insulated coaxial flow that facilitates the storage and use of heat from the depths of the ground in combination with a heat pump.
“The coaxial system allows pumping through larger volumes of water than conventional systems. The possibility to run the system in reverse for cooling or waste energy storage is a great additional advantage, too,” Aosaar describes the benefits of QHeat’s solution.
“Tallinn is growing so rapidly that our current district heating systems are having trouble keeping pace."
Another key benefit of QHeat’s technology is its space efficiency, he continues. Unlike standard shallow well solutions, it requires significantly less surface area, making it particularly well-suited for densely built environments like Tallinn. In fact, Tallinn was the site of Steiger’s first drill in this pilot project, with QHeat providing consultation throughout.
“Tallinn is growing so rapidly that our current district heating systems are having trouble keeping pace,” Aosaar sums up.
This partnership marked significant milestones for both collaborators: it was QHeat’s first international licensing project, and Steiger’s first geothermal at such depths. The company had never drilled a well as deep as nearly 1000 meters before.
“There isn’t much geological nor geothermal information available about Estonia’s deeper crystalline basement, so this was truly a pilot project – not only for the Geological Survey of Estonia that commissioned it, but for us as well.”
In Estonia, a sedimentary bedrock layer sits atop the crystalline basement, requiring the use of two different drilling methods: rotary mud and down-the-hole (DTH). While for instance in Finland, QHeat’s geothermal wells can reach depths of up to 2000 meters by just using DTH drilling. Steiger had to start by drilling with the rotary mud method in the sedimentary bedrock and switch to DTH in the crystalline basement.
“Thanks to QHeat’s expertise and technology and the experience gained, we are much better prepared for the future."
For Steiger, the partnership with QHeat and the Estonian pilot projects as a whole were major learning opportunities that opened the door for future breakthroughs. The experienced drillers encountered challenging ground conditions, prompting them to develop solutions to prevent future issues – such as managing heavy water flow after casing installation, addressing fracture systems, and handling broken pits.
“Thanks to QHeat’s expertise and technology and the experience gained, we are much better prepared for the future. If we encounter geological or technological difficulties, we now know better what to do, how to do it, and how to make the process efficient,” Aosaar says.
They are always there for you. That’s how Hardi Aosaar describes the partnership with QHeat.
“QHeat is the leading expert in geothermal energy, so having the chance to call them at any given time and exchange thoughts is obviously a great opportunity for us.”
“In general, we like to keep our eye on what the Finns are doing. If it works, we do the same."
He keeps the QHeat team up to speed on what’s going on in Estonia, and vice versa. During the pilot projects, QHeat’s team visited the drilling sites in Estonia, and were readily available for any kind of remote consultation relating to the project. In 2024, Steiger’s drillers participated in one of QHeat’s domestic projects, utilising QHeat’s equipment in a drilling project in Salo.
“In general, we like to keep our eye on what the Finns are doing. If it works, we do the same. Since QHeat is already executing two kilometer wells in Finland, then our goal is to follow suit and do the same,” Aosaar says with a smile.
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